流量对抛物面槽式太阳能集热器传热特性影响的实验分析

Experimental Analysis of the Influence of Flow Rate on Heat Transfer Characteristics of Parabolic Trough Solar Collector

抛物面槽式太阳能集热器被广泛应用于中温太阳能工业热利用和高温太阳能热发电领域,然而太阳能间歇性的固有缺陷与供能系统期望的稳定连续运行相悖。通常通过调节流量使变太阳辐照条件下运行的槽式集热器提供相对稳定的有用能量输出,进而对其下游设备的稳定性起着关键作用。为了研究流量变化对集热器瞬态热行为的影响,通过人工调节造成流量的阶跃变化来开展实验,并且研究分析了在不同流量下的雷诺数、努塞尔数和传热流体对流换热系数。

The parabolic trough solar collector is a commercialized and mature concentrating solar collector,which is widely used in the field of medium temperature solar industrial heat utilization and high temperature solar thermal power generation.However,the inherent drawback of solar energy is contrary to the stable and continuous operations expected by the energy supply system.Usually,adjusting the flow rate of the heat transfer fluid is a method to let the collector provide a relatively stable output under varying solar irradiation conditions,which plays a key role in the stability of its downstream equipments.In order to clarify how the change of flow rate affects the transient thermal behaviors of the collectors,this study carried out experiments with the step-change of the flow rate by the manual adjustment,and then carried out the analysis of Reynolds number,Nusselt number and the convective heat transfer coefficient of the heat transfer fluid with different flow rates.